Various mobile or portable electronic devices may have reduced power consumption by operating some of the systems within these devices at low voltages (e.g., 3.0 volts, 1.5 volts, etc.). Such electronic devices often use direct current to direct current converters (“dc to dc converters” or “dc-dc converters”) to “step down” voltages available from their power supplies to the lower voltages used by these systems.
Typical dc-dc converters include switched capacitor dc-dc converters, which may contain one or more switches controlling one or more “flying capacitors.” The switches determine when the flying capacitors charge and discharge to supply power to the load. The flying capacitors may charge from a regulated current source and may discharge at least in part to a “buffer” or output capacitor coupled in parallel with the load.
However, switched capacitor dc-dc converters generally suffer from switching losses. Switching losses include power loss resulting from power used to operate the switches. These switching losses may not scale with the load current being supplied, since in many cases, the operation of the switches is consistent regardless of the load. For example, the switches may require the same energy per switching event regardless of the load, and a same number of switches may be operative for a wide range of load currents supplied by the dc-dc converter.